The present invention concerns a method of manufacturing composite board whereby a continuous coat of mortar reinforced with glass cloth or a similar material is laid onto a continuous core.
The Austrian Patent No. 242,581 discloses a method of manufacturing composite boards with cores of expanded material. The cores are positioned and introduced horizontal and coated with soft mortar. The mortar is compacted with a pivoting cylinder. Downstream of the cylinder glass cloth is removed from a roll, forced down against the top of the mortar, and entrained by the advancing web. Farther downstream another coating of mortar is applied loosely to the first coating and the glass cloth and compacted with another pivoting cylinder.
The two coats of plastic over the expanded-material core of a composite manufactured by the method disclosed in the Austrian Patent No. 242,581 are together much thicker than their framing. They are heavy and inappropriate for such interior structures as tiled walls. Such composites are accordingly primarily employed on flat roofs and facades. In other words, much more mortar is used to embed and attach the glass cloth than is needed for interior construction.
The German Patent No. 3,423,006 C2 discloses a method of manufacturing light-weight structural boards. A woven or knitted fabric is stretched tight over an expanded-material component and covered with a thin coating of water-resistant mortar. The mortar is then smoothed and adheres tight to the fabric. One drawback is that, while the fabric is being stretched, forces can be exerted between it and the plastic that tend to separate the two. Another drawback is that each board is separately covered with fabric and coated with mortar. Such discontinuous production is expensive.
A method of manufacturing similar boards is known from the British Patent No. 1,459,575. A mixer pours a base onto a belt that advances at a constant speed. A doctor distributes the material to a prescribed thickness. A sealant is similarly applied to the base and a surface to the sealant. One drawback to this approach is that the thickness of each layer depends on the speed of the belt and on the skill of the personnel.
The German Patent No. 3,136,935 C1 describes a method of manufacturing board. The core of the board essentially comprises layers of adjacent and parallel mineral fibers. The fibers are oriented at an angle of 10 to 60.degree. to the surface of the board. A sheet of aluminum or plastic is applied to the layers of fiber and a coating of fireproof mortar to the aluminum or plastic.
One drawback to method is that the board is flexible and accordingly appropriate only for wrapping pipes or covering flat and even surfaces.
The German No. 3,444,881 C2 discloses a method of manufacturing board. The core is a layer of mineral fiber, glass staple or wadding for example. The core is more or less compacted to a fraction of the thickness of the final board. A layer of mortar is applied to each side of the core. Glass fibers have been blended into the mortar. This board is not very strong and is appropriate only for surfacing solid concrete walls.